Nanoscale devices that manipulate single electrons of charge e with metrological accuracy are being used at NIST to develop new fundamental electrical standards, such as a capacitance standard
based on counting electrons.
This work is a critical step in the development of the Electron-Counting Capacitance Standard
A team of NIST scientists in collaboration with an intern from the University of Maryland, has made two advances in the development of cryogenic capacitors for use with the Electron-Counting Capacitance Standard
For example, in the case of the capacitance standard
, this problem means that the standard must be stopped every so often to retune the gate charges.
The development of a NIST prototype SET capacitance standard
is described as proceeding along three pathways: (1) a transportable version of the prototype is being constructed for direct comparison with the calculable capacitor at NIST headquarters in Gaithersburg, MD; (2) a detailed uncertainty analysis of all aspects of the standard is being developed; and (3) an effort is under way to design an easy-to-use, robust and automated system with computer control of as many functions as possible.
The electron pump is a critical component of the new SET-based capacitance standard
being developed and detailed modeling of the error mechanisms is a critical step to understanding and improving the performance of the pump.
NIST plans to transfer the frequency dependence data to the Farad Bank and other reference capacitance standards
, so that in the near future, improved capacitance calibrations will be available from NIST for the entire audio frequency range.
Recent work at NIST has resulted in a factor of three decrease in the uncertainty for certain of the highest-level calibrations of fused-silica capacitance standards
. At NIST, capacitance calibrations are based on the SI farad as realized by the NIST Calculable Capacitor.